Liquid crystal display

ABSTRACT

Provided is a liquid crystal display including a plurality of pixels disposed in a matrix of pixel rows and pixel columns, the liquid crystal display including: a plurality of gate lines formed on a first substrate and disposed two between every pixel row; a plurality of data lines formed on the first substrate and disposed one between every two adjacent pixel columns; a common voltage line formed on the first substrate and extending in a pixel row direction along a vertical center of the pixel; and a plurality of pixel electrodes and common electrodes formed on the first substrate and overlapping with each other with an insulating layer therebetween, each pixel electrode positioned in a pixel, and in which two pixel electrodes in the two pixel columns disposed between two adjacent data lines among the plurality of data lines are both connected to any one of the two data lines.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 14/324,868 filed on Jul. 7, 2014, which claimspriority to Korean Patent Application No. 10-2013-0105534, filed on Sep.3, 2013 in the Korean Intellectual Property Office (KIPO), and all thebenefits accruing therefrom under 35 U.S.C. § 119, the contents of theprior applications being herein incorporated by reference.

BACKGROUND

(a) Technical Field

The present invention relates to a liquid crystal display.

(b) Description of the Related Art

Liquid crystal displays, which are one of the most common types of flatpanel displays currently in use, have two sheets of panels that includefield generating electrodes, such as a pixel electrode, a commonelectrode, and the like, and a liquid crystal layer interposedtherebetween. A liquid crystal display generates an electric field inthe liquid crystal layer by applying voltage to the field generatingelectrodes, and the generated electric field determines the direction ofliquid crystal molecules of the liquid crystal layer, thus controllingpolarization of incident light so as to display images. Transmittance ofthe liquid crystal display may be increased as control of the liquidcrystal molecules improves.

In one type of liquid crystal display, both the pixel electrode and thecommon electrode generating the electric field in the liquid crystallayer may be provided on one display panel that also includes aswitching element. In such a liquid crystal display, a signal delay ofthe common voltage applied to the common electrode may occur. In orderto prevent the signal delay of the common voltage, a common voltage linetransferring a common voltage is formed in the pixel area. However,forming the common voltage line in the pixel area may cause an apertureratio of the liquid crystal display to deteriorate.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the disclosure andtherefore it may contain information that does not form the prior artthat is already known to a person of ordinary skill in the art.

SUMMARY

A liquid crystal display having advantages of reducing delay of a signalapplied to a common electrode and preventing deterioration of anaperture ratio of the liquid crystal display is proviced.

A liquid crystal display is provided including a plurality of pixelsdisposed in a matrix of pixel rows and pixel columns, the liquid crystaldisplay including: a plurality of gate lines formed on a first substrateand disposed two between every pixel row; a plurality of data linesformed on the first substrate and disposed one between every twoadjacent pixel columns; a common voltage line formed on the firstsubstrate and extending in a pixel row direction along a vertical centerportion of the pixel; and a plurality of pixel electrodes and commonelectrodes formed on the first substrate and overlapping with each otherwith an insulating layer therebetween, each pixel electrode positionedin a pixel. Two pixel electrodes in the two adjacent pixel columnsdisposed between two adjacent data lines among the plurality of datalines are both connected to any one of the two data lines.

The plurality of data lines may include a first portion and a secondportion which extend in different directions and meet at a center of thepixel area, and the common voltage line may overlap with a meetingportion of the first portion and the second portion of the plurality ofdata lines.

The common voltage line may include a first extension and a secondextension which extend in parallel with the data line, and the firstextension and the second extension may be disposed between the two pixelelectrodes.

The liquid crystal display may further include a second insulationsubstrate facing the first insulation substrate; and a light blockingmember disposed on the second insulation substrate, in which the lightblocking member may overlap with the first extension and the secondextension of the common voltage line.

Edges of the two pixel electrodes may generate a first fringe fieldtogether with the first extension and the second extension of the commonvoltage line, the edges of the two pixel electrodes may generate asecond fringe field together with the common electrode, and directionsof the first fringe field and the second fringe field may be differentfrom each other.

The liquid crystal display may further include a second substrate facingthe first substrate; and a light blocking member formed on the secondsubstrate, in which the first extension and the second extension of thecommon voltage line may not overlap with the light blocking member.

The common voltage line and the common electrode may be connected toeach other through a contact hole formed in the insulating layer, thecommon voltage line may include a contact portion, and the contact holemay overlap with the contact portion.

The contact portion may be disposed between the two pixel electrodes.

An area of the contact portion may be larger than a cross-sectional areaof the contact hole.

An area of the contact portion may be smaller than a cross-sectionalarea of the contact hole.

According to the example embodiments, it is possible to reduce delay ofa signal applied to a common electrode and prevent deterioration of anaperture ratio of the liquid crystal display.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a liquid crystal display according to anexample embodiment.

FIG. 2 is a structural diagram of the liquid crystal display accordingto an example embodiment.

FIG. 3 is a layout view of the liquid crystal display according to anexample embodiment.

FIG. 4 is a cross-sectional view of the liquid crystal display of FIG. 3taken along line IV-IV.

FIG. 5 is a cross-sectional view of the liquid crystal display of FIG. 3taken along line V-V.

FIG. 6 is a layout view of a liquid crystal display according to anotherexample embodiment.

FIG. 7 is a cross-sectional view of the liquid crystal display of FIG. 6taken along line VII-VII.

FIG. 8 is a layout view illustrating a liquid crystal display accordingto another example embodiment.

FIG. 9 is a cross-sectional view of the liquid crystal display of FIG. 8taken along line IX-IX.

FIG. 10 is a layout view illustrating a liquid crystal display accordingto another example embodiment.

FIG. 11 is a cross-sectional view of the liquid crystal display of FIG.10 taken along line XI-XI.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The example embodiments will be described more fully hereinafter withreference to the accompanying drawings. As those skilled in the artwould realize, the described embodiments may be modified in variousdifferent ways, all without departing from the spirit or scope of thepresent invention.

In the drawings, the thickness of layers, films, panels, regions, etc.,are exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element such as a layer, film, region, or substrate is referred to asbeing “on” another element, it can be directly on the other element, orintervening elements may also be present. In contrast, when an elementis referred to as being “directly on” another element, there are nointervening elements present.

Hereinafter, a liquid crystal display according to an example embodimentwill be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating a liquid crystal displayaccording to an example embodiment, and FIG. 2 is a structural diagramof the liquid crystal display according to an example embodiment.

As illustrated in FIG. 1, a liquid crystal display according to anexample embodiment includes a liquid crystal panel assembly 300, a gatedriver 400 and a data driver 500 connected to the liquid crystal panelassembly 300, a gray voltage generator 800 connected to the data driver500, and a signal controller 600 controlling the elements of the displaypanel.

The liquid crystal panel assembly 300 includes a plurality of displaysignal lines G1-G2 n D1-Dm, C1-C2 n, Cv, L1, and L2, and a plurality ofpixels PX connected to the display signal lines and arrangedsubstantially in a matrix form when viewed from an equivalent circuit.

The display signal lines G1-G2 n, D1-Dm, C1-C2 n, Cv, L1, and L2 includea plurality of gate lines G1-G2 n transferring gate signals (referred toas “scanning signals”), data lines D1-Dm transferring data signals,common voltage lines C1-C2 n, a common voltage line connecting portionCv, and dummy lines L1 and L2. The gate lines G1-G2 n extendsubstantially in a row direction and are almost parallel to each other,and the data lines D1-Dm, and the dummy lines L1 and L2 extendsubstantially in a column direction and are almost parallel to eachother. The common voltage lines C1-C2 n extend in parallel to theplurality of gate lines G1-G2 n, and the common voltage line connectingportion Cv connects the plurality of common voltage lines C1-C2 n toeach other and extends in parallel to the data lines D1-Dm.

The dummy line L1 and the dummy line L2 extend substantially across arow direction, around a leftmost edge of the liquid crystal panelassembly 300 and around a rightmost edge of the liquid crystal panelassembly 300, respectively and are almost parallel to the data linesD1-Dm.

As illustrated in FIG. 2, pairs of gate lines, such as Gn+1 and Gn+2,Gn+3 and Gn+4, . . . , are disposed on and below a pixel electrode 191in one row. Further, the data lines D1-Dm are disposed between the pixelelectrodes 191 every two columns. That is, one of the data lines D1-Dmis disposed between each pair of pixel columns. The connection betweenthe gate lines G1-G2 n and the data lines D1-Dm and the pixel electrodes191 will be described in more detail.

Pairs of gate lines G1-G2 n connected above and below the pixelelectrodes 191 are connected to the corresponding pixel electrode 191through a switching element !, which is disposed either above or beloweach pixel electrode 191.

That is, in an odd-numbered pixel row, a switching element Q connectedto a pixel electrode positioned to the left side of the immediatelyadjacent data line D1-Dm (i.e., the data line D1-Dm directly to theright of the pixel electrode) is connected to the upper gate lines G1,G5, G9, . . . , (i.e., Gn, Gn+4 in FIG. 2), and a switching element Qconnected to a pixel electrode positioned to the right side of theimmediately adjacent data line D1-Dm (i.e., the data line D1-Dm directlyto the left of the pixel electrode) is connected to the lower gate linesG2, G6, G10, . . . (i.e., Gn+1, Gn+5 in FIG. 2). In an even-numberedpixel row, connection of the upper gate lines G3, G7, G11, . . . and thelower gate lines G4, G8, G12, . . . and a switching element Q is theopposite to the connection thereof in the odd-numbered pixel row. Thatis, the switching element Q connected to a pixel electrode positioned tothe right side of the immediately adjacent data lines D1-Dm (i.e., thedata line D1-Dm directly to the left of the pixel electrode) isconnected to the upper gate lines G3, G7, G11, . . . , (i.e., Gn+2, Gn+6in FIG. 2) and the switching element Q connected to a pixel electrodepositioned to the left side of the immediately adjacent data lines D1-Dm(i.e., the data line D1-Dm directly to the right of the pixel electrode)is connected to the lower gate lines G4, G8, G12, . . . (i.e., Gn+3,Gn+7 in FIG. 2).

The pixel electrode 191 positioned to the left side of the immediatelyadjacent data lines D1-Dm among the pixel electrodes 191 in theodd-numbered pixel row is connected to the immediately adjacent datalines D1-Dm through the switching element Q, and the pixel electrode 191positioned to the right side of the immediately adjacent data linesD1-Dm is connected to the next adjacent data line to the right of thepixel electrode 191 through the switching element Q. The pixel electrode191 positioned to the left side of the immediately adjacent data linesD1-Dm among the pixel electrodes 191 in the even-numbered pixel row isconnected to the previous adjacent data line to the left of the pixelelectrode 191 through the switching element Q, and the pixel electrode191 positioned to the right side of the immediately adjacent data linesD1-Dm is connected to the immediately adjacent data line through theswitching element Q. Further, the pixel electrode 191 in the firstcolumn and the even-numbered row is connected to the dummy line L1connected to the last data line Dm, and the pixel electrode 191 in thelast column and the odd-numbered row is connected to the dummy line L2connected to the first data line D1.

As described above, the switching element formed at each pixel electrodeis formed at a position which may be more easily connected to theconnected data lines D1-Dm or the dummy lines L1 and L2, that is, aconnection length from the switching element Q to the data line or dummyline may be as short as possible. Accordingly, in the layout illustratedin FIG. 2, the position of the switching element Q is changed for everypixel row. That is, in the odd numbered rows, the switching element Q isformed at an upper right end in the pixel disposed directly to the leftside of the data lines D1-Dm among the pixel pairs, and the switchingelement Q is formed at a lower right end in the pixel disposed directlyto the right side of the data lines D1-Dm.

In the even numbered rows, a formation position of the switching elementQ of the pixel electrode is directly opposite to the formation positionin the adjacent pixel row (which is an odd numbered row). That is, theswitching element Q is formed at a lower left end of the pixel electrodedisposed directly to the left side of the data lines D1-Dm among thepixel pairs, and the switching element Q is formed at an upper left endof the pixel disposed directly to the right side of the data linesD1-Dm.

In the connection of the pixel electrode 191 and the data lines D1-Dmillustrated in FIG. 2, in each pixel row, the switching elements Q oftwo pixel electrodes disposed between two adjacent data lines areconnected to the same data line. That is, in the odd numbered pixel row,the switching elements of two pixel electrodes disposed between two datalines are connected to the data line disposed directly to the right sideof the pair of pixel electrodes, and in the even numbered pixel row, theswitching elements Q of two pixel electrodes disposed between two datalines are connected to the data line disposed directly to the left sideof the pixel pair.

The layout illustrated in FIG. 2 is just one example, and the connectionof the pixel electrodes 191 in the odd numbered rows and the evennumbered rows and the data lines D1-Dm and the gate lines G1-G2 n may bechanged, and further, another connection relationship may be formed.

According to the connection relationship of the pixel electrodes 191 andthe data lines D1-Dm and the gate lines G1-G2 n, the data signalsapplied to the data lines D1-Dm form column inversion, while theadjacent pixel rows form dot inversion.

The common voltage lines C1-Cn are formed for each pixel row andconnected to each other by the common voltage line connecting portion Cvto receive common voltages from the exterior of the display panel.

Hereinafter, the structure of the liquid crystal display illustrated inFIGS. 1 and 2 will be described in detail with reference to FIGS. 3 to5.

FIG. 3 is a layout view illustrating a liquid crystal display accordingto an example embodiment, FIG. 4 is a cross-sectional view of the liquidcrystal display of FIG. 3 taken along line IV-IV, and FIG. 5 is across-sectional view of the liquid crystal display of FIG. 3 taken alongline V-V.

Referring to FIGS. 3 to 5, a liquid crystal display according to anexample embodiment includes a lower panel 100, an upper panel 200, and aliquid crystal layer 3 interposed between the two panels 100 and 200.

First, the lower panel 100 will be described in detail.

A plurality of gate lines 121 a and 121 b and a plurality of commonvoltage lines 131 are formed on a first substrate 110 made oftransparent glass or the like.

The gate lines 121 a and 121 b mainly extend in a horizontal direction,a part of the gate lines 121 a and 121 b protrudes downward or upward toform gate electrodes 124 a and 124 b. The two gate lines 121 a and 121 bare adjacent to each other to make a pair. Alternatively, the top gateline 121 b and the bottom gate line 121 a may not make a pair.

The gate lines 121 a and 121 b include extensions 125 a and 125 b.

Each common voltage line 131 extends in parallel to the gate lines 121 aand 121 b between the gate lines 121 a and 121 b that make a pair, andis disposed at a center of a pixel area, that is the area covered by thepixel electrodes between two gate lines 121 a and 121 b and two datalines 171.

The common voltage line 131 includes a first extension 132 a and asecond extension 132 b which are disposed between two adjacent datalines 171 and extend in parallel to the data line 171.

The gate lines 121 a and 121 b and the common voltage line 131 may bemade, for example, of aluminum-based metal such as aluminum (Al) or analuminum alloy, silver-based metal such as silver (Ag) or a silveralloy, copper-based metal such as copper (Cu) or a copper alloy,molybdenum-based metal such as molybdenum (Mo) or a molybdenum alloy,chromium (Cr), tantalum (Ta), and titanium (Ti). However, the gate lines121 a and 121 b and the common voltage line 131 may also include twolayers having different physical properties, that is, a lower layer (notillustrated) and an upper layer (not illustrated) thereon. The upperlayer may be made of metal having low resistivity, for example,aluminum-based metal such as aluminum (Al) or an aluminum alloy,silver-based metal such as silver (Ag) or a silver alloy, andcopper-based metal such as copper (Cu) or a copper alloy, so as toreduce a signal delay or a voltage drop of the gate lines 121 a and 121b and the common voltage line 131. Unlike this, the lower layer may bemade of another material, particularly, a material having an excellentcontact characteristic with indium tin oxide (ITO) and indium zinc oxide(IZO), for example, chromium (Cr), molybdenum (Mo), a molybdenum alloy,tantalum (Ta), titanium (Ti), or the like. An example of a combinationof materials for the lower layer and the upper layer may include achromium/aluminum-neodymium (Nd) alloy.

A gate insulating layer 140 made of silicon nitride (SiN_(x)) or thelike is formed on the gate lines 121 a and 121 b and the common voltageline 131.

A plurality of semiconductors 154 a and 154 b made, for example, ofhydrogenated amorphous silicon (amorphous silicon is written as anacronym a-Si), polysilicon, or the like is formed on the gate insulatinglayer 140.

A plurality of island-shaped ohmic contacts 163 a (not shown in FIG.),163 b, 165 a (not shown in FIG.), and 165 b which is made of silicide ora material such as n+ hydrogenated amorphous silicon in which n-typeimpurity is doped at high concentration is formed on the semiconductors154 a and 154 b. The ohmic contacts 163 a/163 b and the ohmic contacts165 a/165 b make pairs and are disposed on the semiconductors 154 a/154b.

A data conductor including a plurality of data lines 171 and a pluralityof drain electrodes 175 a and 175 b is formed on the ohmic contacts 163a, 163 b, 165 a, and 165 b and the gate insulating layer 140.

The data line 171 includes a wide end portion (not illustrated) forconnection with another layer or an external driving circuit. The dataline 171 transfers a data signal and mainly extends in a verticaldirection to cross the gate lines 121 a and 121 b.

The data line 171 may have a shaped portion having an angled or curvedshape in order to allow for maximum transmittance of the liquid crystaldisplay, and in this case the angled shape may have a V-lettered shapewhich meets in a middle region of the pixel area. Such a V-letteredshape may be formed with a first portion that extends to the middleregion of the pixel area and a second portion which extends to the nextgate line area form a predetermined angle with the first portion. Thatis, the data line 171 may include a first portion and a second portionextending in different directions, and the first portion and the secondportion meet each other in the middle region of the pixel area to form aV-lettered shape.

The common voltage line 131 described above is formed at a position thatoverlaps with the position at which the first and the second portions ofthe data line 171 meet, referred to herein as the “meeting portion.”

The meeting portion of the first portion and the second portion of thedata line 171 is a portion having the smallest luminance of the liquidcrystal display in the pixel area. Accordingly, it is possible toprevent deterioration of an aperture ratio of the liquid crystal displaydue to the formation of the common voltage line 131.

The data line 171 includes source electrodes 173 a and 173 b. The drainelectrodes 175 a and 175 b include extensions for connection with thepixel electrode 191 to be described below, and one of the ends of thedrain electrodes 175 a and 175 b face the source electrodes 173 a and173 b, and the other of the ends of the drain electrodes 175 a and 175 boverlap with the extensions 125 a and 125 b of the gate lines 121 a and121 b.

One of the ends of the drain electrodes 175 a and 175 b, particularly,an edge of a far side from the data line 171, overlap with theextensions 125 a and 125 b of the gate lines 121 a and 121 b. Then,because a mask for exposing a photosensitive film for the data line maynot be aligned at an accurate position, the data line pattern moves tothe left or the right. As a result, even though the drain electrodes 175a and 175 b move to the left or the right, an area in which the drainelectrodes 175 a and 175 b overlap with the gate electrodes 124 a and124 b and the extensions 125 a and 125 b of the gate lines 121 a and 121b is uniformly maintained. Accordingly, a capacity of a parasiticcapacitor formed by overlapping of the gate conductor and the dataconductor may be uniformly maintained.

The gate electrodes 124 a/124 b, the source electrodes 173 a/173 b, andthe drain electrodes 175 a/175 b form a thin film transistor (TFT)together with the semiconductors 154 a/154 b, and a channel of the thinfilm transistor is formed in the semiconductors 154 a/154 b between thesource electrodes 173 a/173 b and the drain electrodes 175 a/175 b.

The pixel electrode 191 is formed directly on each of the drainelectrodes 175 a and 175 b. The pixel electrode 191 has a planar shape,that is, a plate shape, and is disposed in one pixel area.

A passivation layer 180 is formed on the data conductor 171, 173 a, 173b, 175 a, and 175 b, the gate insulating layer 140, and an exposedportion of the semiconductors 154 a and 154 b, and the pixel electrode191. However, in a liquid crystal display according to another exampleembodiment, the passivation layer 180 may be disposed between the pixelelectrode 191 and the data line 171, and the pixel electrode 191 mayalso be connected with the drain electrodes 175 a and 175 b through acontact hole (not illustrated) formed in the passivation layer 180.

A contact hole 183 exposing the common voltage line 131 is formed in thepassivation layer 180.

A common electrode 270 is formed on the passivation layer 180.

The common electrode 270 has a plurality of cutouts 71 and includes aplurality of branch electrodes 271 defined by the plurality of cutouts71.

The common electrode 270 includes a horizontal connecting portion 272, afirst vertical connecting portion 273 a, and a second verticalconnecting portion 273 b, and the common electrodes 270 disposed inadjacent pixels are connected to each other through the horizontalconnecting portion 272 and the vertical connecting portions 273 a and273 b.

The horizontal connecting portion 272 of the common electrode 270 isdisposed on the gate lines 121 a and 121 b, the first verticalconnecting portion 273 a of the common electrode 270 is disposed on thedata line 171, and the second vertical connecting portion 273 b isdisposed between two adjacent pixel electrodes 191.

The second vertical connecting portion 273 b of the common electrode 270is connected with the common voltage line 131 through the contact hole183 formed in the passivation layer 180.

The common electrode 270 has an opening 274 formed at a positionoverlapping with the thin film transistor forming the switching element.

The cutout 71 and the branch electrode 271 of the common electrode 270are parallel to the data line 171.

Although not illustrated, an alignment layer is coated on the commonelectrode 270 and the passivation layer 180, and the alignment layer maybe a horizontal alignment layer and is rubbed in a predetermineddirection. However, in a liquid crystal display according to anotherexample embodiment, the alignment layer includes a photoreactivematerial to be photo-aligned.

Next, the upper panel 200 will be described.

A light blocking member 220 is formed on a second substrate 210. Aplurality of color filters 230 are further formed on the secondsubstrate 210. The color filters 230 may be disposed on the lower panel100, and in this case, the light blocking member 220 may also bedisposed on the lower panel 100.

An overcoat 250 is formed on the color filter 230 and the light blockingmember 220. The overcoat 250 may be omitted.

An alignment layer, not shown, may be disposed on the overcoat 250.

The liquid crystal layer 3 includes a liquid crystal material havingpositive dielectric anisotropy or negative dielectric anisotropy. Liquidcrystal molecules of the liquid crystal layer 3 are aligned so that longaxes thereof are parallel to the panels 100 and 200, and may be disposedto have pretilt angles in a rubbing direction of the alignment layer.

In the liquid crystal display according to the example embodiment, thepixel electrode 191 has a planar shape formed throughout each pixelarea, and the common electrode 270 has a plurality of branch electrodes271, but according to a liquid crystal display according to anotherexample embodiment, the common electrode 270 has a planar shape formedthroughout each pixel area, and the pixel electrode 191 may have aplurality of branch electrodes defined by the cutouts.

Referring to FIGS. 3 and 5, the contact hole 183 for connecting thecommon voltage line 131 and the common electrode 270 is disposed betweentwo adjacent data lines 171 and disposed between two adjacent pixelelectrodes 191.

Accordingly, it is possible to prevent deterioration of an apertureratio due to the contact hole 183 for connecting the common voltage line131 and the common electrode 270.

According to the liquid crystal display according to the exampleembodiment, the first extension 132 a and the second extension 132 b ofthe common voltage line 131 are disposed between two adjacent data lines171 and disposed between two adjacent pixel electrodes 191. Accordingly,it is possible to prevent light leakage which may occur in the twoadjacent pixel electrodes 191, and thus it is possible to reduce a widthof the light blocking member 220 formed between the two adjacent pixelelectrodes 191. Generally, in order to prevent light leakage due tomisalignment of the light blocking member 220 formed on the upper panel200 and the pixel electrode 191 formed on the lower panel 100, a widthof the light blocking member 220 is largely formed by a misalignmenterror. However, according to the liquid crystal display according to theexample embodiment, the extensions 132 a and 132 b of the common voltageline 131 are formed on the lower panel 100 and disposed between the twopixel electrodes 191 formed between the adjacent data lines 171 toprevent light leakage which may occur between the adjacent pixelelectrodes 191, and as a result, even though the width of the lightblocking member 220 formed in the upper panel 200 is decreased, thelight leakage between the two adjacent pixel electrodes 191 may beprevented. Accordingly, the aperture ratio of the liquid crystal displayincreases.

Therefore, a signal delay of the common voltage applied to the commonelectrode 270 of the liquid crystal display is prevented anddeterioration of the aperture ratio of the liquid crystal display may beprevented.

The common voltages having the same magnitude are applied to the commonvoltage line 131 and the common electrode 270.

Accordingly, a first fringe field generated between edges of the twoadjacent pixel electrodes 191 disposed between the two adjacent datalines 171 and the common voltage line 131 disposed below the pixelelectrode 191, and a second fringe field generated between the edges ofthe two adjacent pixel electrodes 191 disposed between the two adjacentdata lines 171 and the common electrode 270 disposed on the pixelelectrode 191 have the same magnitude, and directions thereof areopposite to each other. Therefore, the first fringe field and the secondfringe field may be offset.

When the fringe field is applied to the liquid crystal moleculesdisposed between the two adjacent pixel electrodes, a mixed color may begenerated between colors displayed by the two adjacent pixels.Accordingly, in the case of a general liquid crystal display, in orderto prevent the mixed color, a distance between the two adjacent pixelelectrodes is largely formed.

However, according to the liquid crystal display according to theexample embodiment, the fringe field between the pixel electrode and thecommon voltage line and the fringe field between the pixel electrode andthe common electrode are offset by forming the extension of the commonvoltage line between the edges of the two adjacent pixel electrodes, andas a result, even though the distance between the two adjacent pixelelectrodes is decreased, it is possible to prevent the mixed colorbetween the colors displayed by the two adjacent pixels. As such, thedistance between the two adjacent pixel electrodes is decreased, andthus the aperture ratio of the liquid crystal display increases.

Next, a liquid crystal display according to another example embodimentwill be described with reference to FIGS. 6 and 7. FIG. 6 is a layoutview illustrating a liquid crystal display according to another exampleembodiment of the present invention, and FIG. 7 is a cross-sectionalview of the liquid crystal display of FIG. 6 taken along line VII-VII.

Referring to FIGS. 6 and 7, the liquid crystal display according to theexample embodiment is almost similar to the liquid crystal displayaccording to the example embodiment described with reference to FIGS. 3to 5. Therefore, detailed description for like constituent elements isomitted.

However, in the liquid crystal display according to the exampleembodiment, unlike the example embodiment described with reference toFIGS. 3 to 5, the common voltage line 131 includes a first contactportion 133 formed at a position where the contact hole 183 is to beformed.

The first contact portion 133 is formed between the two adjacent pixelelectrodes 191 of the liquid crystal display to connect the commonvoltage line 131 and the common electrode 270 without deterioration ofthe aperture ratio of the liquid crystal display.

Because an area of the first contact portion 133 is larger than an areaof the contact hole 183, even though misalignment occurs when thecontact hole 183 is formed, the contact hole 183 may be formed on thefirst contact portion 133.

Accordingly, even though misalignment occurs when the contact hole 183is formed, the common voltage line 131 and the common electrode 270 maybe stably connected to each other through the contact hole 183.

All features of the liquid crystal display according to the exampleembodiment described with reference to FIGS. 3 to 5 may be applied tothe liquid crystal display according to the example embodiment.

Next, a liquid crystal display according to another example embodimentwill be described with reference to FIGS. 8 and 9. FIG. 8 is a layoutview of a liquid crystal display according to another exampleembodiment, and FIG. 9 is a cross-sectional view of the liquid crystaldisplay of FIG. 8 taken along line IX-IX.

Referring to FIGS. 8 and 9, the liquid crystal display according to theexample embodiment is almost similar to the liquid crystal displayaccording to the example embodiment described with reference to FIGS. 3to 5. Therefore, detailed description for like constituent elements isomitted.

However, in the liquid crystal display according to the exampleembodiment, unlike the example embodiment described with reference toFIGS. 3 to 5, the common voltage line 131 includes a third extension 134a and fourth extension 134 b having larger areas than the firstextension 132 a and the second extension 132 b shown in FIG. 3.

As such, the common voltage line 131 includes the third extension 134 aand the fourth extension 134 b having large areas, thereby sufficientlypreventing light leakage which may occur between the two adjacent pixelelectrodes 191. Referring to FIG. 9, according to the liquid crystaldisplay according to the example embodiment, even though the lightblocking member 220 is not formed on the upper panel 200, the lightleakage which may occur between the adjacent pixel electrodes 191 may beprevented. Accordingly, the light blocking member 220 is not formedbetween the adjacent pixel electrodes 191, and as a result, the apertureratio of the liquid crystal display increases.

According to the liquid crystal display according to the exampleembodiment, the fringe field between the pixel electrode and the commonvoltage line, and the fringe field between the pixel electrode and thecommon electrode, are offset by forming the extension of the commonvoltage line between the edges of the two adjacent pixel electrodes, andas a result, even though the distance between the two adjacent pixelelectrodes is decreased, it is possible to prevent the mixed colorbetween the colors displayed by the two adjacent pixels. As such, thedistance between the two adjacent pixel electrodes is decreased, andthus the aperture ratio of the liquid crystal display increases.

All features of the liquid crystal display according to the exampleembodiment described above with reference to FIGS. 3 to 5 may be appliedto the liquid crystal display according to the example embodiment.

Next, a liquid crystal display according to another example embodimentwill be described with reference to FIGS. 10 and 11. FIG. 10 is a layoutview illustrating a liquid crystal display according to another exampleembodiment, and FIG. 11 is a cross-sectional view of the liquid crystaldisplay of FIG. 10 taken along line XI-XI.

Referring to FIGS. 10 and 11, the liquid crystal display according tothe example embodiment is almost similar to the liquid crystal displayaccording to the example embodiment described with reference to FIGS. 3to 5. Therefore, detailed description for like constituent elements isomitted.

However, in the liquid crystal display according to the exampleembodiment, unlike the example embodiment described with reference toFIGS. 3 to 5, the common voltage line 131 includes a second contactportion 135 formed at a position where the contact hole 183 is to beformed.

The second contact portion 135 is formed between the two adjacent pixelelectrodes 191 of the liquid crystal display to connect the commonvoltage line 131 and the common electrode 270 without deterioration ofthe aperture ratio of the liquid crystal display.

An area of the second contact portion 135 is smaller than the area ofthe contact hole 183. The area of the second contact portion 135 issmaller than the area of the contact hole 183, and as a result,deterioration of the aperture ratio due to the contact hole 183 may beprevented.

All features of the liquid crystal display according to the exampleembodiment described above with reference to FIGS. 3 to 5 may be appliedto the liquid crystal display according to the example embodiment.

While example embodiments have been described in connection with what ispresently considered to be practical example embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the disclosure, including the appended claims.

<Description of symbols> 110, 210: Insulation substrate 3: Liquidcrystal layer 121a, 121b: Gate line 124a, 124b: Gate electrode 131:Common voltage line 140: Gate insulating layer 154a, 154b: Semiconductor163a, 163b, 165a, 165b: Ohmic contact 171: Data line 173a, 173b: Sourceelectrode 175a, 175b: Drain electrode 180: Passivation layer 191: Pixelelectrode 270: Common electrode

What is claimed is:
 1. A liquid crystal display comprising: a gate lineand a data line disposed on a first substrate; a transistor connected tothe gate line and the data line on the first substrate; a pixelelectrode connected to the transistor on the first substrate anddisposed in a pixel in a layout view; an insulating layer disposed onthe pixel electrode; a common electrode disposed on the insulating layerand overlapping the pixel electrode; a common voltage line disposed on asame layer with the gate line on the first substrate and extending alonga centerline of the pixel, the common voltage line comprising anextended contact portion extended from the common voltage line and afirst extension and a second extension extending from the common voltageline in different directions, each of the different directions formingat least one non-right angle with the common voltage line; and a contacthole disposed in the centerline and overlapping the extended contactportion of the common voltage line; wherein the common electrodedisposed on the pixel electrode is directly connected to the commonvoltage line through the contact hole, and wherein the first extensionand the second extension are disposed between two pixel electrodes, andwherein the two pixel electrodes are disposed between two data linesadjacent to each other and the two pixel electrodes are physically andelectrically separated from each other.
 2. The liquid crystal display ofclaim 1, wherein: the data line includes a first portion and a secondportion that extend in different directions and meet on the centerlineof the pixel area, and the common voltage line overlaps with a meetingportion of the first portion and the second portion of the plurality ofdata lines.
 3. The liquid crystal display of claim 2, wherein: the firstextension and the second extension extend in parallel with,respectively, the first portion and the second portion of the data line.4. The liquid crystal display of claim 3, further comprising: a secondsubstrate facing the first substrate; and a light blocking member formedon the second substrate, wherein the light blocking member overlaps withthe first extension and the second extension of the common voltage line.5. The liquid crystal display of claim 2, wherein: the contact holeextends to the extended contact portion.
 6. The liquid crystal displayof claim 5, wherein: an area of the extended contact portion is largerthan a cross-sectional area of the contact hole.
 7. The liquid crystaldisplay of claim 5, wherein: an area of the extended contact portion issmaller than a cross-sectional area of the contact hole.
 8. The liquidcrystal display of claim 1, wherein: the common voltage line includes afirst extension and a second extension which extend in parallel with thedata line, and the first extension and the second extension are disposedbetween two pixel electrodes adjacent to each other.
 9. The liquidcrystal display of claim 8, further comprising: a second substratefacing the first substrate; and a light blocking member formed on thesecond substrate, wherein the light blocking member overlaps with thefirst extension and the second extension of the common voltage line. 10.The liquid crystal display of claim 1, wherein: the contact hole extendsto the extended contact portion.
 11. The liquid crystal display of claim10, wherein: an area of the extended contact portion is larger than across-sectional area of the contact hole.
 12. The liquid crystal displayof claim 10, wherein: an area of the extended contact portion is smallerthan a cross-sectional area of the contact hole.